In recent years, active studies have been conducted on SON (Self Organizing Network), which autonomously optimizes radio parameters and network configurations, in radio communication systems such as cellular systems. Standardization of SON functions is under way also in 3GPP LTE (Long Term Evolution) (NPL 1). Forms of use of SON include technologies for optimization of cell coverage and capacity (Coverage and Capacity Optimization: CCOpt) and the like. To implement CCOpt, it is necessary that each base station should know communication loads on its neighboring base stations. Since the X2 interface is prescribed between base stations that are close to each other for them to exchange various information (NPL 2), it is possible to acquire communication loads on neighboring base stations by using this X2 interface.
Moreover, the situation of mobile telecommunications is that a plurality of systems such as WCDMA (Wideband Code Division Multiple Access) and LTE, or public LANs (Local Area Networks), coexist, and further a plurality of operators coexist also in cellular networks. In such a multi-network environment, user equipment need to know a communication load in each network in order to select and connect to a network where higher-speed communication is possible.
Furthermore, PTL 1 discloses a method in which the degrees of communication loads in cells in vicinity are determined and then cell selection or re-selection is performed. According to the system of PTL 1, the Ec/No of a pilot signal received from another cell is measured, whereby the degree of concentration of calls in this another cell is determined and used for decision in cell selection or re-selection.